CN202918256U - Filter amplifier - Google Patents
Filter amplifier Download PDFInfo
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- CN202918256U CN202918256U CN 201220593993 CN201220593993U CN202918256U CN 202918256 U CN202918256 U CN 202918256U CN 201220593993 CN201220593993 CN 201220593993 CN 201220593993 U CN201220593993 U CN 201220593993U CN 202918256 U CN202918256 U CN 202918256U
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- filter
- acoustic wave
- surface acoustic
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Abstract
Provided is a filter amplifier, composed of a first mixer, a first saw filter, a variable-gain amplifier, a second saw filter and a second mixer which are successively connected, wherein the first mixer accepts incoming signals and first local oscillator signals and down converts the incoming signals into intermediate frequency signals; the intermediate frequency signals are performed filtering by the first saw filter and are outputted to the variable-gain amplifier for signal amplification; amplified signals are inputted to the second saw filter to perform second filtering; and then filtered signals are up converted into a frequency where the incoming signals are originally located through the second mixer for outputting; a first local oscillator circuit is in connection with the first mixer and is used for providing stable first local oscillator signals for down conversion of the first local oscillator circuit; the first local oscillator signal frequency changes with the change of the incoming signals to guarantee a fixed value of the intermediate frequency signals; the second local oscillator circuit is in connection with the second mixer. According to the utility model, DTT (Digital Terrestrial TV) signal transmission can be perfectly compatible with 4GLTE (Long Term Evolution) signals.
Description
Technical field
The utility model belongs to the radiofrequency signal processing technology field, be specifically related to a kind of filter amplifier, this filter amplifier adopts Surface Acoustic Wave Filter (saw filter) to realize 4G LTE(the 4th third-generation mobile communication technology) network and digital terrestrial television (DTT) compatibility.
Background technology
4G LTE (Long Term Evolution, Long Term Evolution) project is the evolution of 3G, starts from the meeting Toronto meeting of 3GPP in 2004.4G LTE improves and has strengthened the aerial access technology of 3G, adopts OFDM and MIMO as the sole criterion of its wireless network evolution.
4G LTE standard is to DTT(Digital Terrestrial TV, digital terrestrial television) has higher requirement, in the 4th generation,, (4G LTE) mobile network service had a strong impact on frequency at the 790-862MHz(61-69 channel in worldwide quick introducing) the transmission of DDT, even the transmission channel upper limit of following DTT signal is reduced to 60 channels (790MHz) and the 1MHz definitions of bandwidth of 790-791MHz is cut apart DTT signal and 4G LTE network signal for " buffering area ", also be harsh to the current device requirement, 59 channels in the DTT signal, " defence frequency band " that 60 channels and LTE download between the passband only has 1MHz; (the LTE signal strength signal intensity approximately surpasses DTT signal 20 ~ 25dB) and the intensity of LTE signal substantially exceeds the signal of DTT, do not increase a suitable LTE traffic filter if allow these two kinds of signal Free propagations, the TV programme that 59,60 channels in the DTT signal must occur can't normally be watched.
So DTT filter amplifier product of the various different brands of using in the whole world at present, must be upgraded to the filtering performance that can provide enough strong, in the frequency band of 1MHz, suppress to surpass 30dB near DTT59,60 channel LTE downstream signals, make the DTT signal can normal transmission and the purpose of application thereby reach.And at this stage, because any integrated circuit or LC resonance filter all can't reach so good filtering performance, so the whole world does not all have the product of good solution to come out at present.
Summary of the invention
The utility model purpose is to overcome the defective of prior art, and a kind of filter amplifier is provided, and this filter amplifier can suppress the LTE signal at 1MHz and surpass 30dB intensity, makes DTT signal transmission perfection be compatible with 4G LTE signal.
Technical scheme
The technical scheme that realizes the utility model purpose is: a kind of filter amplifier, formed by the first frequency mixer, the first Surface Acoustic Wave Filter, the controllable amplifier that gains, the second Surface Acoustic Wave Filter and the second frequency mixer that connect successively, described the first frequency mixer is accepted input signal and the first local oscillation signal, and input signal is down-converted to intermediate-freuqncy signal; Described the first Surface Acoustic Wave Filter is carried out exporting to after the filtering the controllable amplifier of described gain to described intermediate-freuqncy signal and is carried out signal and amplify, amplified signal inputs to the second Surface Acoustic Wave Filter again and carries out again filtering, and filtered signal is exported upconvert to the frequency at the original place of described input signal through described the second frequency mixer after again; The first local oscillation circuit be connected the first frequency mixer and connect, be used to described the first local oscillation circuit down-conversion that the first stable local oscillation signal is provided, the first local oscillator signal frequency changes along with the variation of described input signal, guarantees that intermediate-freuqncy signal is always fixed value; The second local oscillation circuit be connected the second frequency mixer and connect, be used to described the second frequency mixer up-conversion that the second local oscillation signal is provided, the output signal of the second frequency mixer and the frequency range of described input signal are conformed to.
As further improvement of the utility model, described the first and second Surface Acoustic Wave Filter adopt the Surface Acoustic Wave Filter of intermediate frequency 140MHZ, bandwidth 8MHz.
For the DTT system product, LTE base station down signal can produce its CH60 channel and disturb, because only have the spacing frequency of 1MHz between the two.In order so guarantee the normal reception of DTT CH60 channel, to need an extraordinary low pass filter of squareness factor (or band is logical) just can be implemented in filtering LTE base station signal in the so narrow bandwidth.The Frequent Filters such as LC, cavity, medium can't realize this narrow-band filtering demand.Make a general survey of various filters, also only have at present Surface Acoustic Wave Filter can realize the high suppression characteristic in this arrowband.In case selected Surface Acoustic Wave Filter, the centre frequency that it is corresponding and bandwidth will be fixed up, but because the particularity of DTT signal so that this product needs that not only high inhibition is arranged, and need to be carried out the frequency spectrum shift function.This scheme just can not directly be chosen only for Surface Acoustic Wave Filter corresponding to filtering LTE signal(-) carrier frequency so.Intermediate frequency Surface Acoustic Wave Filter commonly used has 70MHZ and 140MHZ, according to the integrated demand of the distribution of DTT actual spectrum and double conversion local oscillator complexity, the Surface Acoustic Wave Filter of we final choice two-stage intermediate frequency 140MHZ, bandwidth 8MHz and the frequency spectrum shift function that double conversion is realized high inhibition.
The beneficial effects of the utility model are:
(1) the utility model has been realized the automation of radiofrequency signal, the filter and amplification function of deciding frequency, deciding bandwidth, deciding gain of precision effectively;
(2) the utility model has been realized in the 1MHz bandwidth the inhibition of radiofrequency signal up to 30dB;
(3) the utility model has been realized having kept the essential frequency translation function of DTT signal modulating equipment in the situation that embeds Surface Acoustic Wave Filter;
(4) the utility model has perfectly been realized the transmission of 4G LTE signal and DTT signal and the compatibility of application;
(5) total system possesses good replicability and autgmentability, and extremely low for upgrading and the improvement cost of original product.
Description of drawings
Fig. 1 is the circuit structure block diagram of the utility model embodiment 1.
Embodiment
Be described further below in conjunction with drawings and Examples.
As shown in Figure 1, a kind of filter amplifier 10, formed by the first frequency mixer (MIXER1) 1, the first Surface Acoustic Wave Filter (SAW1) 2, the controllable amplifier (VGA) 3 that gains, the second Surface Acoustic Wave Filter (SAW2) 4 and the second frequency mixer (MIXER2) 5 that connect successively, the first frequency mixer (MIXER1) 1 is accepted input signal RFIN and the first local oscillation signal LO1, and input signal RFIN is down-converted to intermediate-freuqncy signal; 2 pairs of intermediate-freuqncy signals of the first Surface Acoustic Wave Filter (SAW1) are carried out exporting to after the filtering the controllable amplifier of gain (VGA) 3 and are carried out signal and amplify, amplified signal inputs to the second Surface Acoustic Wave Filter (SAW2) 4 again and carries out again filtering, and filtered signal upconverts to output signal output RFOUR after the frequency at the original place of input signal RFIN through the second frequency mixer (MIXER2) 5 again; The first local oscillation circuit 6 be connected frequency mixer 1 and connect, be used to the first local oscillation circuit 1 down-conversion that the first stable local oscillation signal is provided, the first local oscillation signal LO1 frequency changes along with the variation of input signal RFIN, guarantees that intermediate-freuqncy signal is always fixed value; The second local oscillation circuit 7 be connected frequency mixer 5 and connect, be used to described the second frequency mixer up-conversion that the second local oscillation signal LO2 is provided, the output signal RFOUT of the second frequency mixer and the frequency range of input signal RFIN are conformed to.
The first frequency mixer 1 adopts the frequency mixer (model: RF2052) the radiofrequency signal RFIN through 75 ohm of F connector inputs is done down-frequency conversion of U.S. RFMD company.The first local oscillation circuit 6 uses common crystals to produce the first local oscillation signal LO1 input mixer, for down-conversion provides stable local oscillator input.The 140MHz that the first Surface Acoustic Wave Filter 2 adopts Wixi Huapu Microelectronic Co., Ltd. to produce, the Surface Acoustic Wave Filter of bandwidth 8MHz is to down-conversion signal filtering.The controllable amplifier 3 that gains adopts the step gain adjustable amplifier (model: ADPZ8368ACPZ) signal after the filtering is done gain adjustment of U.S. ADI company.The 140MHz that the second Surface Acoustic Wave Filter 4 adopts Wuxi HuaPu to produce, the Surface Acoustic Wave Filter of bandwidth 8MHz is to again filtering of down-conversion signal; The second frequency mixer 5 adopts the frequency mixer (model: RF2052) the radiofrequency signal RFIN through 75 ohm of F connector inputs is done upward frequency conversion of U.S. RFMD company.The second local oscillation circuit 7 adopts common crystals to produce the second local oscillation signal LO2 input mixer, for up-conversion provides the local oscillator input.Output signal RFOUT can upconvert to the frequency range that needs according to actual needs.Output signal RFOUT transmits for the user by 75 ohm of F connector outputs and uses.
It is high that filter amplifier is encapsulated in the wide x of the long x of 30x25x50cm() upper and lower covers adds in the tin box of inhaling the ripple sponge material, and both sides adopt plastic clip to fix, and make all around to be screwed, and have realized the good shielding of product and have made things convenient for actual installation.
For the relatively high input signal of frequency, in order to obtain higher filtering inhibition, the method that usually adopts be frequency down conversion to fixed intermediate frequency, then intermediate-freuqncy signal is carried out filter amplifying processing.Because intermediate-freuqncy signal is easily processed in this case, and intermediate-frequency filter realizes well, suppresses so the scheme that we upconvert to primary frequency again by the filter and amplification intermediate-freuqncy signal obtains higher filtering.We have adopted secondary Surface Acoustic Wave Filter (SAW), have adopted the controllable amplifier of a stage gain (VGA) between the two-stage Surface Acoustic Wave Filter, so that whole link gain has controllability.For input signal RFIN, carry out first down-conversion, carry out again filtering of filter and amplification after being converted to intermediate frequency, and then upconvert to frequency and the final output at original place.Local oscillation signal LO1 provides stable local oscillator input for down-conversion, and changes along with the variation of input signal, guarantees that intermediate-freuqncy signal is always fixed value.Local oscillation signal LO2 provides stable local oscillator input for up-conversion, and can upconvert to according to actual needs on the frequency range that needs.
Claims (3)
1. filter amplifier, it is characterized in that, this filter amplifier is comprised of the first frequency mixer, the first Surface Acoustic Wave Filter, the controllable amplifier that gains, the second Surface Acoustic Wave Filter and the second frequency mixer that connect successively, described the first frequency mixer is accepted input signal and the first local oscillation signal, and input signal is down-converted to intermediate-freuqncy signal; Described the first Surface Acoustic Wave Filter is carried out exporting to after the filtering the controllable amplifier of described gain to described intermediate-freuqncy signal and is carried out signal and amplify, amplified signal inputs to the second Surface Acoustic Wave Filter again and carries out again filtering, and filtered signal is exported upconvert to the frequency at the original place of described input signal through described the second frequency mixer after again; The first local oscillation circuit be connected the first frequency mixer and connect, be used to described the first local oscillation circuit down-conversion that the first stable local oscillation signal is provided, the first local oscillator signal frequency changes along with the variation of described input signal, guarantees that intermediate-freuqncy signal is always fixed value; The second local oscillation circuit be connected the second frequency mixer and connect, be used to described the second frequency mixer up-conversion that the second local oscillation signal is provided, the output signal of the second frequency mixer and the frequency range of described input signal are conformed to.
2. filter amplifier according to claim 1 is characterized in that, described the first and second Surface Acoustic Wave Filter adopt the Surface Acoustic Wave Filter of intermediate frequency 140MHZ, bandwidth 8MHz.
3. filter amplifier according to claim 1 is characterized in that, described filter amplifier is encapsulated in upper and lower cover to be added in the tin box of inhaling the ripple sponge material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220593993 CN202918256U (en) | 2012-11-12 | 2012-11-12 | Filter amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220593993 CN202918256U (en) | 2012-11-12 | 2012-11-12 | Filter amplifier |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202918256U true CN202918256U (en) | 2013-05-01 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220593993 Expired - Lifetime CN202918256U (en) | 2012-11-12 | 2012-11-12 | Filter amplifier |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202918256U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT202100008621A1 (en) | 2021-04-08 | 2022-10-08 | Valter Ambrogiani | MECHANISM FOR ENGRAVING AND SPLITTING TILES AND RELATED PRODUCTION PROCEDURE |
| IT202100008660A1 (en) | 2021-04-08 | 2022-10-08 | Valter Ambrogiani | ENGRAVING GROUP WITH QUICK BEARING DISASSEMBLY |
-
2012
- 2012-11-12 CN CN 201220593993 patent/CN202918256U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT202100008621A1 (en) | 2021-04-08 | 2022-10-08 | Valter Ambrogiani | MECHANISM FOR ENGRAVING AND SPLITTING TILES AND RELATED PRODUCTION PROCEDURE |
| IT202100008660A1 (en) | 2021-04-08 | 2022-10-08 | Valter Ambrogiani | ENGRAVING GROUP WITH QUICK BEARING DISASSEMBLY |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130501 |
|
| CX01 | Expiry of patent term |